NDP Series Air-Operated Double Diaphragm Pumps
Operating as a 1:1 positive displacement technology, these pneumatically driven systems safely and reliably transfer highly variable fluid volumes using compressed gas. Known for a patented, stall-free air valve design and robust bolted construction, these units are engineered to maximise operational uptime.
Pneumatic Excellence: The NDP Series combines proven pneumatic engineering with innovative air valve design, eliminating the failure modes that plague traditional electric pump solutions in hazardous, volatile, and abrasive environments.
Product Overview
The NDP Series AODD pumps represent the pinnacle of pneumatic positive displacement technology for applications where traditional electric pumps fail or pose safety risks. These systems are highly versatile and specifically engineered for environments characterised by flammable vapours, explosive atmospheres, shear-sensitive slurries, or extreme fluid variability. Driven entirely by compressed pneumatic pressure, the NDP delivers constant, reliable performance without introducing electrical hazards — making it ideal for mining operations, chemical plants, petrochemical facilities, and anywhere safety and compliance demands a non-electric solution.
The architecture centres on two flexible diaphragms connected by a common centre shaft, with an intuitive air-valve control system that alternates pneumatic pressure to drive consistent, infinitely variable flow rates. This simplicity, combined with robust bolted construction and readily available replacement components, ensures minimal downtime and maximum operational reliability.
Core Operating Principle
AODD technology operates on a beautifully simple principle: two diaphragms working in perfect synchronisation to create reliable, pulsation-controlled positive displacement.
The Pumping Cycle
The central air valve directs compressed air behind one diaphragm, pushing it outward to create a discharge stroke that forces liquid out of the chamber. Simultaneously, the connected opposite diaphragm is pulled inward, creating a vacuum that draws new liquid into its respective chamber.
Directional Flow Control
The system continuously alternates this cycle. Four internal ball check valves ensure fluid travels in a single direction — entering through the bottom suction manifold and exiting through the top discharge manifold, preventing any backflow or siphoning.
Variable Flow Control
Volumetric flow rates are infinitely variable, governed entirely by the volume and pressure of the compressed air supplied to the unit. Simply adjust your air supply, and the pump instantly adapts — no speed controllers, no complex electronics, no maintenance hassles.
System Advantages & Operational Capabilities
Intrinsic Safety & ATEX Compliance
Driven entirely by pneumatics, these pumps are easily grounded and inherently explosion-proof. ATEX-compliant options are available for volatile and flammable environments, making them the industry standard in gas processing, petrochemicals, and mining applications where electrical ignition sources pose unacceptable risk.
Robust Fluid Handling
The NDP Series is capable of pumping highly viscous liquids, shear-sensitive fluids, and slurries with high solids content — up to 40% by weight. Whether handling tar, oil, mud, or abrasive mining slurries, the simple, sealed design handles everything without degradation or performance loss.
Exceptional Operational Resilience
These pumps can safely run dry without damaging internal components, tolerate deadheading indefinitely, and provide excellent self-priming and suction lift capabilities. This makes them ideal for transfer applications where suction lines are exposed to air or variable inlet conditions.
Simplified Maintenance
Robust bolted construction and easily replaceable common components dramatically reduce maintenance time and spare part costs. There are no mechanical seals, no gland packing, and no motor to service — just straightforward diaphragm and valve replacement with standard tooling.
Material Specifications & Thermal Limits
To accommodate everything from simple water transfer to ultra-high purity semiconductor chemicals and highly corrosive acids, AODD pumps are highly customisable across pump body materials and elastomer selections.
Pump Body Materials
Elastomer Selection
Performance Specifications
Typical Applications
- Mining and mineral processing — slurry transfer, ore handling, tailings management
- Chemical manufacturing — acid transfer, caustic handling, multi-phase media
- Food processing — thick, abrasive, or shear-sensitive products
- Emergency response and containment — spill recovery, hazardous waste transfer
- Petrochemical and refining operations — crude transfer, tank cleaning, hazardous fluid handling
- Paint and coating transfer — pigments, resins, high-viscosity formulations
- Pharmaceutical and laboratory — hazard-free transfer of sensitive compounds
- Hazardous area facilities (ATEX) — gas processing, explosive atmosphere environments
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